1. Field of the Invention
The present invention relates to a sheet processing apparatus having a plurality of processing unit.
2. Description of the Related Art
A conventional sheet processing apparatus is connected to an image forming apparatus which forms an image onto a sheet. The sheet processing apparatus has plural sheet processing units such as a sheet folding unit, a sheet punching unit, an insert sheet feeder unit, a booklet making unit and sheet stapling unit, by which the sheet processing apparatus can vary sheet processing. All such sheet processing units are supplied with power simultaneously, and if one unit malfunctions, all sheet processing units are not supplied with a power until the malfunctioning sheet processing unit is fixed. That is, even though sheet processing units other than the broken sheet processing unit can process a sheet, all sheet processing units do not work.
In view of this problem, Japan patent application publication 10-265121 shows that a broken sheet processing unit is not supplied with power and sheet processing units other than the broken sheet processing unit are supplied with power. This permits the normal sheet processing units to work while the broken sheet processing unit is waiting for fixing.
However, in a case where a broken sheet processing unit has a sheet feed path which selects between transport of a sheet to another sheet processing unit and transport of a sheet to a sheet processing station within the broken sheet processing unit, if the broken sheet processing unit has selected the path to the sheet processing station when the broken sheet processing unit is not supplied with power, the sheet cannot be transported to the normal sheet processing units which remain supplied with power.
An object of the present invention is to provide sheet processing apparatus which can transport a sheet to an operative sheet processing unit through a malfunctioning sheet processing unit which is not supplied with power.
In one aspect, the present invention provides a sheet processing apparatus for processing sheets from an image forming apparatus comprising a first processing unit for processing a sheet, said first processing unit including a processing station for processing a sheet, a first path for transporting a sheet therethrough, and a second path for transporting a sheet to said processing station, a second processing unit for processing the sheet transported from said first processing unit, a power supply for supplying power independently to said first processing unit and said second processing unit, wherein said first processing unit selects said first path when said first processing unit is not supplied with power by said power supply.
Preferably, in the sheet processing apparatus, said first processing unit includes leading means for leading a sheet to one of said first and second paths alternatively, and said leading means leads a sheet to said first path when said first processing unit is not supplied with the power by said power supplier.
More preferably, in the above sheet processing apparatus, said processing unit includes driving means for driving said leading means to select said second path, wherein said driving means is not supplied with the power when said first processing unit is not supplied with the power by said power supplier.
Also, in the above sheet processing apparatus, said leading means is driven by said driving means so that said leading means selects said second path, wherein said leading means is pulled by elastic means so that said leading means selects said first path.
Also, in the above sheet processing apparatus, said leading means is a flapper, and said driving means is a solenoid, and said elastic means is a spring.
Specifically, the sheet processing apparatus further comprises an invalidation terminal for designating which unit is not supplied with power, wherein said power supply supplies power in accordance with a designation at said invalidation terminal.
More specifically, in the above sheet processing apparatus, said invalidation terminal includes first and second switches corresponding to said first and second processing units respectively, said first and second switches are grounded and are connected to first and second resistors respectively which are connected to a power source, said power supply includes a first voltage detector for detecting a voltage between said first or second switch and its respective resistor, and said power supply supplies power when a voltage detected by said first voltage detector is a predetermined voltage.
Also, the above sheet processing apparatus further comprises a unit attachment detector for detecting an attachment state of said first and second processing units which are detachable from said sheet processing apparatus, wherein said first or second switches is connected to its respective resistor through a connector when said first or second unit is attached, and is disconnected from its respective resistor when said first or second unit is detached, wherein said unit attachment detector includes a second voltage detector for detecting a voltage between said first or second resistor and said connector, wherein said unit attachment detector includes a third switch which is grounded and connected to a third resistor which is connected to a point between said first or second switches and said connector, and wherein said unit attachment detector turns said third switch on and detects the attachment state based on a voltage by detected said second voltage detector.
Also, in the sheet processing apparatus, said first processing unit is comprised by a sheet folder for folding a sheet.
Also, the sheet processing apparatus further comprises a display for displaying an indication when at least one of said first and second processing unit is not supplied with a power.
Also, the sheet processing apparatus further comprises a transmitter for transmitting a notification to a service center when at least one of said first and second processing unit is not supplied with a power.
In another aspect of the invention, the present invention provides a controlling method of a sheet processing apparatus for processing sheets from an image forming apparatus, said sheet processing apparatus including a first processing unit for processing a sheet, said first processing unit including a processing station for processing a sheet, a first path for transporting a sheet therethrough, and a second path for transporting a sheet to said processing station, and a second processing unit for processing the sheet transported from said first processing unit, said controlling method comprising a step for supplying power independently to said first processing unit and said second processing unit, and a step for selecting said first path when said first processing unit is not supplied with power by said power supply.
By virtue of the above invention, even if said first processing unit is not supplied with power by said power supply, a sheet is transported to said second processing unit through said first processing unit. This permits said sheet processing apparatus to use said second processing unit when said first processing unit is not supplied with power even if a sheet must go through said first processing unit.
Other objects and features of the invention will be apparent from the following description and the drawings.